In video after video, Elliot Rodger roamed Santa Barbara like an invisible man, narrating his lonely existence in a strange, clinical tone, consumed by a feeling of total alienation.

"Look at them," Rodger said to his camera phone, staring at a couple on a picnic bench at the beach. "He's in heaven right now, sitting on this beautiful beach, kissing her, feeling her love, while I'm sitting here alone, 'cause no beautiful girl wants to be my girlfriend."

But that appearance of childlike guilelessness — a 22-year-old man lamenting that he was still a virgin and expressing the simple desire to be loved by a woman — gave way to cold rage, then smirking pledges of revenge to come.

"I don't know why you girls haven't been attracted to me, but I will punish you, for it is an injustice," he said. "I'll take great pleasure in slaughtering all of you. You will finally see that I am the superior one, the true alpha male."

He posted eight such videos on YouTube on Friday evening before, officials say, he went on a rampage. Authorities said he stabbed three people to death at his apartment building in Isla Vista; opened fire on women standing outside a sorority, killing two; and then fatally shot someone at a nearby deli. After a gun battle with deputies, he was found dead in his BMW with what officials believe was a self-inflicted gunshot wound.

Shootings near UC Santa Barbara

In other mass killings, authorities have had to grope for reasons behind the attacks. But Rodger trumpeted his motives, posting the videos and sending a 137-page typed diatribe titled "My Twisted World: The Story of Elliot Rodger" to an online acquaintance.

Together they showed a spiral of self-pity and pining for his childhood that warped into a hatred of women and the men with whom they had relationships.

A child of privilege and divorce, with a taste for Gucci and Prada, Rodger was the son of Peter Rodger, a Hollywood director and photographer, who was an assistant director on the first "Hunger Games" movie. Elliot Rodger was raised in Woodland Hills and attended Santa Barbara City College, according to his social media accounts.

If only one pretty girl had shown some form of attraction to me, the Day of Retribution would never happen. I'd never even consider it.— Mass shooting suspect Elliot Rodger

An attorney for his father said Rodger was diagnosed as a high-functioning patient with Asperger's syndrome and had trouble making friends.

In Rodger's screed, he said his parents had arranged for him to see a psychiatrist, Dr. Charles Sophy. But he did not elaborate further.

The ramblings describe the internal turmoil of a young man at once both arrogant and pathetic, unable to see a better future, sinking deeper into despair and anger.

He wrote that he was born in England — his father British, his mother Chinese — and went to an upscale private school. He moved to Woodland Hills when he was 5, and his parents divorced when he was 7, which he called a "life-changing event." He remained close to his mother but had a falling out with his father that lasted several years. After the divorce, he said, he realized he was uncool and timid with "a dorky hairstyle" and became self-conscious about his race.

"I was shy and unpopular.... On top of this was the feeling that I was different because I am of mixed race. I am half white, half Asian, and this made me different from the normal fully white kids that I was trying to fit in with."

He said he dyed his hair blond to fit in but was increasingly bullied by ninth grade.

"I felt very small, weak, and above all, worthless. I cried by myself at school every day."

The evolution of his breakdown is not clear from his text, but he wrote of losing his only friend sometime around the beginning of 2012.

"He blatantly said he didn't want to be friends anymore. He didn't even deign to tell me why.... It was the ultimate betrayal. I thought he was the one friend I had in the whole world who truly understood me."

He wrote that his mother bought him the BMW to give him confidence, but it didn't. Seeing any couple set him off. In particular he vented about Indian, Asian and black men dating the blond women he desired.

An earlier plan to exact revenge on women backfired. He wrote that he tried to shove "girls" at a party over a ledge, but he couldn't do it, and then men rushed to him and pushed him over.

"When I landed, I felt a snap in my ankle, followed by a stinging pain. I slowly got up and found that I couldn't even walk. I had to stumble, and stumble I did. I tried to get away from there as fast as I could."

But he realized someone had taken Gucci sunglasses his mother had given him, and went back to get them. The same people he had tangled with before began mocking him and calling him names, then dragged him into the driveway to beat him up, he wrote. He staggered away in pain.

The neighbor, who asked not to be identified, said he had tried to get Rodger to hang out and party with him and others in the communal courtyard. Rodger usually said no, and the few times he agreed, "he just sat in the chair and stared at everyone the entire time."

Seeing Rodger injured, the neighbor asked what happened. Rodger said he was jumped by a group of men.

"I'm going to kill them, and kill myself," the neighbor recalled him saying.

Rodger wrote that he first began to plan his "Day of Retribution" in the spring of 2013. He bought his first gun at "Goleta Gun and Supply," a Glock 34 with $700 he had saved from money given to him by his parents and grandmothers.

"After I picked up the handgun, I brought it back to my room and felt a new sense of power," he wrote. "If only one pretty girl had shown some form of attraction to me, the Day of Retribution would never happen. I'd never even consider it."

He wrote that he next bought a Sig Sauer P226 for $1,100.

As he planned the attack, he left a trail of bitter comments on online forums.

The Southern Poverty Law Center collected a string of racist and misogynistic comments he made on a site called PuaHate.com. In one he ridiculed an Asian man trying to date a white girl, and said it was "rage-inducing" to see a "black guy chilling with 4 hot white girls."

The videos give a more intimate view of his pathos. One afternoon, he was walking through the parking lot of the Sandpiper Golf Club on the bluffs just west of Isla Vista.

"I come here to admire the whole beauty and serenity of the place," he said, affecting a haughty voice. "The world is such a beautiful place. It's such a tragedy that I've had such a pathetic life in it, all because of the cruelty of humanity and women."

He said he went there regularly to watch the sunset because usually there were no couples to envy.

He approached his car, and the camera caught his reflection on it. "There's me, in all my fabulousness," he said with disdain. "Elliot Rodger. I am so awesome."

He sat in the driver's seat.

"Sex, love, companionship — I deserved those things.... But girls are not sexually attracted to me."

His tone turned more menacing.

"That's a problem I'm going to rectify. I, in all my magnificence and power, I will not let this fly."

With a smirking snort, he signed off. "It's an injustice that needs to be dealt with."